Technical Field
The present disclosure generally relates to systems, methods, and articles for planning and generating paths for tools used to manufacture objects.
Description of the Related Art
Multi-axis machining is a manufacturing process where computer numerically controlled (CNC) tools that move in multiple ways are used to manufacture objects by removing excess material. Systems used for this process include waterjet cutting systems, laser cutting systems, plasma cutting systems, electric discharge machining (EDM), and other systems. Typical multi-axis CNC tools support translation in 3 axes and support rotation around one or multiple axes. Multi-axis machines offer several improvements over other CNC tools at the cost of increased complexity and price of the machine. For example, using multi-axis machines, the amount of human labor may be reduced, a better surface finish can be obtained by moving the tool tangentially about the surface, and parts that are more complex can be manufactured, such as parts with compound contours.
High-pressure fluid jets, including high-pressure abrasive waterjets, are used to cut a wide variety of materials in many different industries. Abrasive waterjets have proven to be especially useful in cutting difficult, thick, or aggregate materials, such as thick metal, glass, or ceramic materials. Systems for generating high-pressure abrasive waterjets are currently available, such as, for example, the Mach 4™ 5-axis abrasive waterjet system manufactured by Flow International Corporation, the assignee of the present invention, as well as other systems that include an abrasive waterjet cutting head assembly mounted to an articulated robotic arm. Other examples of abrasive waterjet cutting systems are shown and described in Flow's U.S. Pat. Nos. 5,643,058 and 8,423,172, which are incorporated herein by reference. The terms “high-pressure fluid jet” and “jet” should be understood to incorporate all types of high-pressure fluid jets, including but not limited to, high-pressure waterjets and high-pressure abrasive waterjets. In such systems, high-pressure fluid, typically water, flows through an orifice in a cutting head to form a high-pressure jet (or “beam”), into which abrasive particles are combined as the jet flows through a mixing tube. The high-pressure abrasive waterjet is discharged from the mixing tube and directed toward a workpiece to cut the workpiece along a designated path, commonly referred to as a “toolpath.”
Various systems are currently available to move a high-pressure fluid jet along a designated path. Such systems may commonly be referred to, for example, as three-axis and five-axis machines. Conventional three-axis machines mount the cutting head assembly in such a way that it can move along an x-y plane and perpendicular along a z-axis, namely toward and away from the workpiece. In this manner, the high-pressure fluid jet generated by the cutting head assembly is moved along the designated path in an x-y plane, and is raised and lowered relative to the workpiece, as may be desired. Conventional five-axis machines work in a similar manner but provide for movement about two additional non-parallel rotary axes. Other systems may include a cutting head assembly mounted to an articulated robotic arm, such as, for example, a 6-axis robotic arm which articulates about six separate axes.
Computer-aided manufacturing (CAM) processes may be used to efficiently drive or control such conventional machines along a designated path, such as by enabling two-dimensional (2D) or three-dimensional (3D) models of workpieces generated using computer-aided design (i.e., CAD models) to be used to generate code to drive the machines.
For example, FIG. 1A illustrates a 3D CAD solid model 100 of an object to be manufactured by cutting away material from a workpiece using a tool, such as a waterjet cutting system. The object includes a compound contour or beveled surface 102 that includes an angled upper bevel face 102A having an edge 104 adjacent to a top face 106, an angled lower bevel face 102B having an edge 108 adjacent a bottom face (not shown), and a vertical middle bevel face 102C extending between the upper bevel face 102A and the lower bevel face 102C (i.e., a “k-bevel”).
To generate a toolpath for cutting the beveled surface 102 of the object, a user may create three non-compound beveled CAD solid models using a CAD application, one CAD solid model for each cut through the workpiece that will ultimately define the beveled faces 102A-C of the original object to be manufactured. FIG. 1B illustrates a first CAD solid model 110 having a cut face 112 that corresponds to the upper bevel face 102A of the object and spans from a top face 114 of the CAD solid model 110 to a bottom face (not shown) thereof (i.e., non-compound beveled). FIG. 1C illustrates a second CAD solid model 116 having a vertical cut face 118 that corresponds to the middle bevel face 102C of the object and spans from a top face 120 to a bottom face (not shown) thereof. FIG. 1D illustrates a third CAD solid model 122 having a cut face 124 that corresponds to the lower bevel face 102B of the object and spans from a top face 126 to a bottom face thereof. For objects with numerous bevels or “compound contours,” the user may need to create several CAD solid models to represent the various required cuts.
The three CAD solid models 110, 116, and 122 may be imported into a CAM application or system and combined to produce a combined CAM solid model 128 shown in FIG. 1E. The operator and/or the CAM system may then select and sequence the cut paths for creating the object depicted by the original CAD solid model 100 in FIG. 1A. As shown, the combined CAM solid model 128 does not resemble the original CAD solid model 100 shown in 1A. Thus, a user of the CAM system and/or operator may have difficulty visualizing or determining which cuts are needed and in what sequence the cuts should be performed. Further, any modifications made to the original CAD solid model 100 may require the user to open the CAD system and recreate or modify each of the three CAD solid models 110, 116, and 112 that represent the cut faces of the original CAD solid model, and then reimport the modified CAD solid models into the CAM system to create a modified combined CAM solid model. For objects having multiple bevels or contours, this process can be expensive, time-consuming, and prone to errors.
Accordingly, there is a need for an improved system and method to plan and generate machining paths for beveled or compound contoured surfaces within a CAD/CAM system.